1. Field of the Invention
The present invention generally relates to adsorbent units for use with refrigeration system accumulators. More specifically, this invention relates to a desiccant bag for use with an automotive air-conditioning accumulator, wherein the desiccant bag integrally fastens to a suction tube assembly by locating against a clasp portion of an oil pickup filter that is mounted to a bight portion of the suction tube.
2. Description of the Related Art
It is common to place an adsorbent unit in an accumulator of a refrigeration system to adsorb moisture and impurities in the refrigerant. An accumulator typically includes a housing having a closed bottom end, and usually includes a J-shaped suction tube extending downwardly toward the closed bottom end of the housing.
Adsorbent units typically mount in some fashion to the xe2x80x9cJ-tubexe2x80x9d and include a fabric bag having desiccant material therein. The fabric bag typically includes a flap extending from the bag and having an aperture therein. The aperture is usually placed over one end of the J-tube to secure the bag in place within the housing. For example, U.S. Pat. No. 4,116,649 to Cullen et al. teaches use of a self-retaining adsorbent bag for use with an accumulator. Cullen et al. disclose the bag as having a flexible flap with an aperture therein for mounting over the end of a conduit. The fit or difference in size between the diameter of the aperture and the diameter of the conduit is specified as 0.005xe2x80x3 (0.127 mm). Such a tight fit makes it difficult to assemble the bag to the conduit.
Similarly, U.S. Pat. No. 5,802,868 to Riemenschneider teaches an improved saddle type adsorbent unit for use in a refrigerant receiver of an air-conditioning system. Riemenschneider discloses a refrigerant accumulator having a housing with a bottom wall, a sidewall, and a U-shaped pipe having a return bend adjacent the bottom wall and having first and second pipe portions extending upwardly from the return bend along the sidewall. A filter body extends downwardly from the return bend. An adsorbent unit is disposed within the housing and includes first and second porous fabric adsorbent containers having inner and outer end portions. A connecting member connects the inner end portions of the first and second containers and is positioned between the first and second pipe portions spaced away from the return bend. A tab extends outwardly from the outer end portion of the first container and has an aperture therein that is force fit around the filter body. Unfortunately, the Riemenschneider adsorbent unit involves a more expensive and more complicated saddlebag unit. Furthermore, the filter body must be force fit through the aperture in the bag to fasten the bag within the housing, and it is not clear how the filter body is retained to the return bend.
In other examples, disclosed in U.S. Pat. Nos. 5,837,039 and 5,914,456 to LeConey et al., an adsorbent packet is adapted for positioning within a housing having a fluid flow tube having a pair of legs connected by a bight portion with a filter extending therefrom. The absorbent packet is formed with identical first and second pouches formed of tubular porous polyester felt material. Each of the pouches include sealed upper ends fused together to form an intermediate portion, and further include oppositely disposed sealed lower ends having apertures formed therein. The pouches are adapted for disposing the sealed lower ends in overlapping relation whereby the apertures thereof are in registry one over the other mounted snugly fit to the filter.
Similarly, U.S. Pat. No. 6,083,303 to LeConey et al. discloses an adsorbent packet for use in a canister having a tube disposed therein with a filter housing protruding therefrom. The filter housing includes a clasp portion circumscribing the tube and includes a flange and filter media portion extending integrally downwardly from the clasp portion. The adsorbent packet includes a flange portion having an opening therein defined by a rigid collar portion that is snap-fit to the filter media and flange portion of the filter housing. Unfortunately, the LeConey et al. references, especially the snap-fit arrangement of the xe2x80x98303 patent, require a tight fit between the apertures of the adsorbent packets and the enlarged flanges of the filter bodies that necessitates use of tight tolerances so that the apertures will not pass back over the enlarged flange once assembled. Additionally, the tight fits required by the LeConey et al. references present an ergonomic problem wherein an assembler must repeatedly exert significant force to snap-fit the adsorbent packet to the filter, thereby potentially leading to repetitive stress injuries. Finally, the difficulty in assembling the packet to the filter results in a higher process cycle time, thereby increasing manufacturing costs.
Accordingly, what is needed is a refrigerant vessel assembly having a desiccant bag therein that integrally fastens to a portion of a suction tube assembly. The desiccant bag economically assembles to the suction tube without the need for a close tolerance fit therebetween and without the need to force fit an aperture of the desiccant bag to another component so as to avoid repetitive stress injuries during assembly and to decrease cycle time of the manufacturing process to reduce costs.
According to the present invention, a desiccant bag is provided for use in an accumulator of an air-conditioning system for an automotive vehicle. The accumulator is of the type that has a suction tube with an inlet leg, an outlet leg, and a bight portion therebetween. The bight portion of the suction tube has a pickup filter mounted thereto that has a clasp circumscribing the suction tube and has a filter body portion extending integrally from the clasp. The desiccant bag includes a fabric casing, a desiccant material sealed within the fabric casing, and a flexible flap extending from the fabric casing. The flexible flap includes an aperture therethrough such that the filter body portion of the pickup filter passes freely therethrough so that a portion of the flexible flap mounts to a portion of the clasp. The aperture may also define a locating edge at one end thereof for locating against a portion of the clasp of the pickup filter to hold the desiccant bag in position on the pickup filter while the fabric casing is tucked between the legs of the suction tube.
In another aspect of the present invention, an accumulator of an air conditioning system for an automotive vehicle is provided. The accumulator includes a suction tube that has an inlet leg, an outlet leg, and a bight portion between the inlet and outlet legs. A pickup filter is mounted to the bight portion of the suction tube and has a clasp circumscribing a portion thereof, with the clasp having a flange extending therefrom with flange teeth thereon. A body portion integrally extends from the clasp with a desiccant bag being mounted thereto. The desiccant bag includes a flap extending from one end thereof, with the flap having an aperture therethrough such that the filter body portion of the pickup filter passes freely therethrough so that a portion of the flexible flap mounts to a portion of the clasp. In several embodiments, the aperture may also define a locating edge at one end thereof for locating against a portion of the clasp of the pickup filter to hold the desiccant bag in position on the pickup filter while the fabric casing is tucked between the legs of the suction tube.
In a further aspect of the present invention, a method of assembling the desiccant bag within the accumulator is disclosed. The method includes the following steps: providing a suction tube having an inlet leg, an outlet leg, and a bight portion between the inlet and outlet legs; providing a pickup filter mounted to the bight portion of the suction tube, the pickup filter having a clasp circumscribing a portion of the bight portion and having a flange extending therefrom, the pickup filter further having a body portion connected with the clasp; providing a desiccant bag having a casing and a flap extending from one end of the casing, the flap having an aperture therethrough; locating the flap of the desiccant bag to a portion of the clasp of the pickup filter; pulling the desiccant bag such that the flap further locates to the clasp of the pickup filter; wrapping the desiccant bag around the bight portion of the suction tube such that the body portion of the pickup filer passes freely through the aperture; and tucking the desiccant bag between the inlet and outlet legs of the suction tube to further retain the desiccant bag in place within the accumulator.
Accordingly, it is an object of the present invention to allow greater dimensional variation between components, particularly between an aperture of a desiccant bag and a corresponding attachment feature on a suction tube, so as to reduce assembly time and cost. Therefore, there is no need for tight tolerances on components and tight fits between the components. Specifically, the present invention eliminates the need to forcibly snap fit a tab aperture of a desiccant bag over a sensitive pickup filter screen. Rather, a locating edge of the tab aperture firmly engages a portion of the clasp of the pickup filter and is pulled tightly thereagainst to assist in retaining the desiccant bag to the suction tube. The desiccant bag of the present invention is more completely retained to the suction tube when a casing of the bag is tucked between the legs of the suction tube.
It is another object of the present invention to immobilize a desiccant bag in the proper location between the legs of the J-tube in order to protect the bag from abrasion from rubbing against sidewalls of a housing, and to protect the bag from contact with the sidewalls and any associated heat that is generated during the manufacturing process.
It is still another object of the invention to provide an easily serviceable or replaceable self-retaining desiccant bag for an accumulator that does not require any external straps, ties, wires, or clips to retain the bag in place and does not require any specially cutout geometry to be embossed or formed in the fabric casing.
It is yet another object of the invention to provide an accumulator and self-retaining desiccant bag for use with a standard pickup filter.
It is a further object to provide a self-retaining desiccant bag for an accumulator that locates more positively to a pickup filter, and is more robust to staying in place in comparison to prior art designs.
It is still a further object to provide a self-retaining desiccant bag that does not require force fitting a filter through an aperture in the desiccant bag.
It is yet a further object to provide a self-retaining desiccant bag that is easier to assemble to an associated accumulator in order to reduce repetitive stress injury, reduce cycle time, and thereby reduce manufacturing costs to achieve a more economical accumulator.
These objects and other features, aspects, and advantages of this invention will be more apparent after a reading of the following detailed description and appended claims taken in conjunction with the accompanying drawings.